LOS ALTOS prefixes in area code 650
NANPA records 28 assigned NXX blocks to rate center LOS ALTOS in area code 650, 3.9% of the 717 blocks assigned in the code. A rate center is the billing geography a block is allocated to – NANPA truncates the name to ten characters, so read it as a NANPA label rather than a town. 14 holders hold those blocks, the largest being PACIFIC BELL (6), ONVOY, LLC - CA (4), MCIMETRO ACCESS TRANSMISSION SERVICES LLC (3). The earliest assignment on record here is 2001-09-21 and the most recent 2025-12-05. 23 of them are in thousands-block pooling, so those prefixes are shared between carriers in 1,000-number lots.
Prefixes assigned here
| Prefix | Holder of record | Assigned | Pooled | In service |
|---|---|---|---|---|
| 650-209 | TPx U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | – | yes | yes |
| 650-229 | Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC | – | yes | yes |
| 650-305 | T-Mobile T-MOBILE USA, INC. | 2002-09-19 | yes | yes |
| 650-383 | AT&T TELEPORT COMMUNICATIONS AMERICA, LLC - CA | – | yes | yes |
| 650-397 | Bandwidth BANDWIDTH.COM CLEC, LLC - CA | – | yes | yes |
| 650-405 | AT&T NEW CINGULAR WIRELESS PCS, LLC | 2018-05-08 | yes | yes |
| 650-469 | Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC | – | yes | yes |
| 650-471 | TPx U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | – | yes | yes |
| 650-472 | Lumen LEVEL 3 COMMUNICATIONS, LLC - CA | – | yes | yes |
| 650-492 | AT&T NEW CINGULAR WIRELESS PCS, LLC | 2002-01-28 | yes | yes |
| 650-518 | T-Mobile METROPCS, INC. | 2001-09-21 | yes | yes |
| 650-559 | AT&T PACIFIC BELL | – | yes | yes |
| 650-668 | FRACTEL, LLC | 2020-07-10 | yes | yes |
| 650-680 | T-Mobile T-MOBILE USA, INC. | 2016-07-15 | yes | yes |
| 650-768 | Windstream PAETEC ITEL, LLC | 2025-12-05 | yes | yes |
| 650-770 | Onvoy ONVOY, LLC - CA | 2016-01-29 | yes | yes |
| 650-774 | Onvoy ONVOY, LLC - CA | 2023-06-26 | yes | yes |
| 650-782 | TON80 COMMUNICATIONS, LLC | 2022-02-18 | yes | yes |
| 650-823 | AT&T NEW CINGULAR WIRELESS PCS, LLC | – | no | yes |
| 650-887 | Onvoy ONVOY, LLC - CA | – | yes | yes |
| 650-900 | Onvoy ONVOY, LLC - CA | – | yes | yes |
| 650-917 | AT&T PACIFIC BELL | – | no | yes |
| 650-935 | Verizon MCIMETRO ACCESS TRANSMISSION SERVICES LLC | – | yes | yes |
| 650-941 | AT&T PACIFIC BELL | – | no | yes |
| 650-946 | Comcast COMCAST PHONE OF CALIFORNIA, LLC | – | yes | yes |
| 650-947 | AT&T PACIFIC BELL | – | yes | yes |
| 650-948 | AT&T PACIFIC BELL | – | no | yes |
| 650-949 | AT&T PACIFIC BELL | – | no | yes |
The holder is who received the block from the numbering administrator. It is not necessarily the carrier serving a given number: numbers move with their owners, and a pooled block is shared.
Who holds the blocks
| Holder | Brand | Blocks | Share here |
|---|---|---|---|
| PACIFIC BELL | AT&T | 6 | 21.4% |
| ONVOY, LLC - CA | Onvoy | 4 | 14.3% |
| MCIMETRO ACCESS TRANSMISSION SERVICES LLC | Verizon | 3 | 10.7% |
| NEW CINGULAR WIRELESS PCS, LLC | AT&T | 3 | 10.7% |
| U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS | TPx | 2 | 7.1% |
| T-MOBILE USA, INC. | T-Mobile | 2 | 7.1% |
| TELEPORT COMMUNICATIONS AMERICA, LLC - CA | AT&T | 1 | 3.6% |
| BANDWIDTH.COM CLEC, LLC - CA | Bandwidth | 1 | 3.6% |
| LEVEL 3 COMMUNICATIONS, LLC - CA | Lumen | 1 | 3.6% |
| METROPCS, INC. | T-Mobile | 1 | 3.6% |
| FRACTEL, LLC | – | 1 | 3.6% |
| PAETEC ITEL, LLC | Windstream | 1 | 3.6% |
| TON80 COMMUNICATIONS, LLC | – | 1 | 3.6% |
| COMCAST PHONE OF CALIFORNIA, LLC | Comcast | 1 | 3.6% |
Frequently asked
Which prefixes belong to LOS ALTOS in area code 650?
28 blocks: 209, 229, 305, 383, 397, 405, 469, 471, 472, 492, 518, 559 and 16 more, all listed in the table above.
Which carriers have numbers in LOS ALTOS?
PACIFIC BELL (6 blocks), ONVOY, LLC - CA (4 blocks), MCIMETRO ACCESS TRANSMISSION SERVICES LLC (3 blocks), NEW CINGULAR WIRELESS PCS, LLC (3 blocks), U.S. TELEPACIFIC CORP. DBA TPX COMMUNICATIONS (2 blocks), T-MOBILE USA, INC. (2 blocks). These are the holders on record; the carrier actually serving a given number can differ, because numbers move with their owners.
Is LOS ALTOS a city?
It is a rate center – the unit NANPA allocates number blocks to. Its name is abbreviated to ten characters and is not necessarily a settlement: we print it as recorded rather than guess at the full name.